As a great portion of the homes and businesses in Rockaway Beach would be damaged in a Cascadia mega-quake Tsunami it is very import to understand how a Tsunami works. Your lives might depend on understanding the differences in a local and distant Tsunami. Located 60-100 miles off of our shoreline lays the “Cascadia Subduction Zone”. An area where two of the great land mass plates meet. One of the plates is trying to dive under the other, and as that happens, pressure builds and when we get a sudden slippage, we get a large earthquake and associated Tsunami. This is called a “local” Tsunami. In this case, you will feel the earth shake for several minutes. THAT IS YOUR WARNING….DO NOT WAIT, AS SOON AS THE GROUND STOPS SHAKING IMMEDIATELY HEAD FOR HIGH GROUND. First wave, of many, may hit our area within 8 min. The first wave is not normally the largest. These waves will have significant impact on our community. Water, sewer, power, roads, and bridges will be damaged. Our area will experience both an earthquake and associated Tsunami’s. However, in a mega-quake type scenario, generated by the Cascadia Subduction Zone, all areas west of the Cascades, from Northern California to the tip of Vancouver Island will have major damage from the earthquake. Supplies coming in will take a very long time, (possibly over 30 days), to reach our community. Emergency planners say this will be much worse than what we saw with Hurricane Katrina.
A Tsunami coming from Alaska, or elsewhere in the Pacific Rim, is called a “distant” Tsunami. We will have early notification and the expected damage to infrastructure will be much less. Scientists can now accurately project the arrival and size of the waves. Because these waves travel a very long distance the damage they create will be much less. For most of these waves people just need to get off of the beach areas and possibly the first dune.
If you hear the Fire Hall Tsunami siren, which will be a steady tone for 3 minutes, first off relax. Turn on your local radio or TV and follow the directions. This is not a time to panic or flee! Just follow the directions.
We have had a lot of confusion about Tsunamis, and our state is aggressively trying to reduce the chaos. A recent example about the confusion that “distant” tsunami’s caused happened when we learned that Chile experienced a large earthquake and Tsunami’s were headed to North America. In our county a few folks went out to Barview jetty to watch the waves come. In other areas of the state, some people were told to get off of the beach. Why? Scientists had predicted a 5 inch wave (which is what we received) but this information didn’t get disseminated correctly.
A fishing boat generates a bigger wave than this!! Rockaway Beach, along with the entire west coast is actively involved in a coast wide educational process to help eliminate confusion and save lives.
Lastly, here in Rockaway Beach we use a fire siren to alert our responders. This siren will be an up and down wailing for 45-60 sec. Our fire siren is located at the fire station.
Please take the time to educate your friends, family, and visitors to the differences in our siren sounds and what the proper responses to each of these sounds are.
If you have questions please contact City Hall at (503) 355-2291.